USS Indianapolis. USS Indianapolis was a Portland-class cruiser who holds a place in history due to the circumstances of her sinking, which led to the greatest single loss of life at sea in the history of the United States Navy. On July 30, 1945, shortly after delivering critical parts for the first atomic bomb to be used in combat to the United States air base at Tinian, the ship was torpedoed by an Imperial Japanese Navy submarine. Of 1,196 crewmen aboard, approximately 300 went down with the ship. The remaining crew of 880 men faced exposure, dehydration and shark attacks as they waited for assistance while floating with few lifeboats and almost no food or water. The Navy learned of the sinking when survivors were spotted four days later by the crew of a PV-1 Ventura on routine patrol. Only 317 sailors survived. 10†x 8†black and white photograph of the ship signed by five survivors: Harlan Twible “Ensign Harlan Twible, USN,†Ed Brown “Ed Brown S 1/C,†Ed Harrell “Ed Harrell USMC,†Michael Kuryla “Michael N. Kuryla, Jr. COX†and Giles McCoy “Giles G. McCoy USMC.â€